I have created a workflow in BPM suite and assigned it to a role, say that role has 4 users in it.What my expectation is if an user from this role initate the workflow than he can only do the process and the workflow should be hidden to other three users.Is it possible or any other workaround for this

There are several ways to have the creator of the instance be the only one to see it in an Interactive activity downstream in the process.

One thing you need to ensure initially is to have the "creator" predefined variable set to a valid user id. This is done for you automatically if you have an Interactive initiator activity in your process. With this initiator, whoever initiates the instance is assigned to the "creator" predefined variable. If you don't have an initiator Interactive activity in your process (e.g. your process is invoked using a Start Message or Signal event or is invoked as a subprocess from another process's Call activity), then you need to set the user id of the person you want to be the creator. This can be done by either:
1. opening properties of an Interactive activity -> click the "Implementation" tab -> expand "Advanced" -> set the user id in the "Initiator" field or
2. opening properties of an Interactive activity -> click the "Implementation" tab -> click "Data Associations" -> with the "Input" tab selected, expand "execData" in the right -> set the "creator" attribute to the user id

Once you are sure you have a valid user id set to the "creator" predefined variable, you can automatically assign this person to work item instances once they reach the downstream interactive activities in the process in a variety of diffent ways but the simplest is to open the human task -> click the "Assignment" tab -> select the "default.DefaultPerformer" icon in the middle -> click the "Edit icon -> change the "Build a list ..." dropdown to "Names and expressions" -> click the plus icon -> "add user" -> change the "Data type" to "By Expression" -> change the "Value" by clicking the "..." button -> on the left, expand "task" -> select "task:creator" and then insert it into the expression.